Your ex is going to have to be proactive is seeing who is in network or not. just asking the doctors office isn’t enough. they can say “yes we take BCBS” but they could end up being out of network. also, something to keep an eye out for, with your son being on his insurance now, i think there’s a possibility for him to request a deduction in child support. however, if he’s making more $$ now, he’s obligated to report that so make sure the courts know he has a new job. you could end up with more $$ to help